Continuous rendering apparatus

ABSTRACT

An improved apparatus and method are provided for continuous dry rendering of animal products, together with an improved cooker for use with such apparatus and method, wherein such products are comminuted to define particles having a predetermined size range and such particles are cooked in the cooker while continuously moving the particles therethrough at a rate which is sufficient to free the fats from the solid constituents. The cooker may be maintained at subatmospheric pressure or alternatively one section of the cooker may be operated under pressure. The comminuted particles are delivered to the cooker with a minimum amount of ambient air and such particles are constantly stirred during cooking while simultaneously scraping substantially the entire inside surface of the cooker to thereby assure optimum cooking efficiency with minimum loss of animal products.

United States Patent Bredeson et al.

CONTINUOUS RENDERING APPARATUS Inventors: Dean K. Bredeson, Piqua, Ohio;

John R. Harrison, Camden, S.C.; Earl A. N. Johnson, Edmonds, Wash.

Assignee: The French Oil Mill Machinery Company, Piqua, Ohio Filed: Apr. 24, 1972 Appl. No.: 246,749

[52] US. Cl. 23/280; 23/285; 23/2905; 260/4126 [51] Int. Cl..... .B01d 43/00; B01j 3/00; Cl1b 1/12 [58] Field of Search ..23/280, 285, 290, 23/290.5; 137/599, 601; 251/304; 259/68, 69; 260/4126 [56] References Cited UNITED STATES PATENTS 1,082,303 12/1913 Carr 23/290.5 1,196,597 8/1916 Sheppard, Jr..... 23/2905 3,248,180 4/1966 Kilpatrick 23/285 3,272,599 9/1966 Allbright et al... 23/280 X 3,288,825 11/1966 Keith 23/280 X 3,295,982 l/1967 Hickey et al 23/280 X 3,506,407 4/1970 Keith l 23/280 3,538,973 11/1970 Levin 23/280 X 3,572,656 3/1971 Oshima 137/601 X FOREIGN PATENTS OR APPLICATIONS 1,932,898 2/1970 Germany 23/290 Primary Examiner-Morris O. Wolk Assistant ExaminerMichael S. Marcus Attorney, Agent, or FirmBiebe1, French & Bugg [5 7] ABSTRACT An improved apparatus and method are provided for continuous dry rendering of animal products, together with an improved cooker for use with such apparatus and method, wherein such products are comminuted to define particles having a predetermined size range and such particles are cooked in the cooker while continuously moving the particles therethrough at a rate which is sufficient to free the fats from the solid constituents. The cooker may be maintained at subatmospheric pressure or alternatively one section of the cooker may be operated under pressure. The comminuted particles are delivered to the cooker with a minimum amount of ambient air and such particles are constantly stirred during cooking while simultaneously scraping substantially the entire inside surface of the cooker to thereby assure optimum cooking efficiency with minimum loss of animal products.

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PATENTEU Aum 2 ms v8 wmm m8 N9 Q -wE wmm CONTINUOUS RENDERING APPARATUS BACKGROUND OF THE INVENTION Numerous apparatus and methods have been proposed previously for the continuous rendering of animal products such as fat, bone, offal, etc. to produce substantially clear liquid fat and solid materials in the form of meal or pressed meal cake. These previously proposed apparatus and methods are either too complicated and expensive for practical use or are very inefficient because they tend to lower the quality of or degrade products being rendered while requiring excessive amounts of utilities in the form of electric power steam and water.

It has also been found that the continuous atmospheric cookers proposed heretofore and used in the previously proposed systems must be operated at temperatures which cause scorching and burning of the animal products passing therethrough, thereby lowering quality and nutritive value of meal and tallow or grease. Further, it is generally very difficult to heat the interiors of these previous cookers to assure uniform heating throughout the entire cooker volume and those surfaces which are heated are usually overheated to assure adequate cooking causing sticking of products thereto and scorching thereof; and, this scorching results in progressively poorer heating or products in the cooker and a corresponding progressive degradation of products and a lowering of the efficiency of the entire rendering system.

SUMMARY OF THE INVENTION This invention provides an improved apparatus and method for the continuous dry rendering of all types of animal products, including fats, tissue, bone, hide, fleshings or the like, and also provides an improved continous cooker for use with this apparatus and method.

The animal products are comminuted to define particles having a predetermined size range and such particles are cooked in the cooker while continuously moving the particles therethrough at a rate which is sufficient to free the fats from the solid constituents. The cooker is comprised of a plurality of two or more sections which may provide cooking under subatmospheric, atmospheric, or above atmospheric pressure conditions or any desired combination of these conditions. When a particular section of the cooker is operated under subatmospheric pressure conditions the meal and tallow or grease exiting therefrom have minimum color and maximum nutritive value. The comminuted particles are delivered to the cooker with a minimum amount of ambient air and the cooker has a plurality of fixed heated surfaces providing efficient heating of the central portion of such cooker. The cooker also has dual-purpose means while providing both stirring of the particles during cooking and simultaneous scraping of practically the entire area of its heated surfaces to thereby assure optimum cooking efficiency with minimum loss of animal products.

Other details, objects, uses, and advantages of this invention will be apparent from the following description, the accompanying drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show present exemplary embodiments of this invention, in which FIG. 1 is a schematic view illustrating one exemplary embodiment of the apparatus and method of this invention;

FIG. 2 is a plan view with parts in cross section and parts broken away particularly illustrating the relative positions of certain components of the apparatus of FIG. 1 including the cooker, components for providing and delivering comminuted animal products to the cooker, and components downstream of the cooker for separating the liquified fats from the solids;

FIG. 3 is a view with parts in cross section and parts broken away taken essentially on the line 33 of FIG.

FIG. 4 is a view with parts in cross section and parts broken away particularly illustrating the cooker utilized in the apparatus and method of FIG. 1;

FIG. 5 is a view of the cooker with parts broken away viewed from the left end of FIG. 4;

FIG. 6 is a view of the cooker viewed from the right end of FIG. 4;

FIG. 7 is an enlarged view of the left end portion of the cooker of FIG. 4 with parts in cross section, parts in elevation, and parts broken away;

FIG. 8 is a view to a reduced scale taken on the line 88 of FIG. 7;

FIG. 9 is an enlarged cross-sectional view taken on the line 9-9 of FIG. 4 illustrating a central stationary partition of the cooker and also illustrating valve assemblies and associated openings used to control the flow of animal products across such partition;

FIG. 10 is a view of a typical gate comprising each valve assembly of FIG. 9;

FIG. 11 is a view taken on the line l111 of FIG. 7;

FIG. 12 is a fragmentary view with parts in cross section taken essentially on the line l212 of FIG. 9;

FIG. 13 is a fragmentary perspective view particularly illustrating the construction and relative position of a typical blade used to scrape a fixed vertical heating surface in the cooker of FIG. 4;

FIG. 14 is a schematic showing of a modified cooker which has a pair of central shaft portions capable of being rotated independently;

FIG. 15 is a side view similar to the central portion of FIG. 1 I particularly showing a pair of added substantially radial blades used to aid in scraping an associated vertical planar heating surface; and

FIG. 16 is a fragmentary view taken essentially on the I line l616 of FIG. 15.

DESCRIPTION OF EXEMPLARY EMBODIMENT Introduction Reference is now made to FIG. 1 of the drawings which illustrates one exemplary embodiment of the apparatus and method of this invention which is designated generally by the reference numeral 20. In general, animal products including fats, bones, skins, offal, etc,. are comminuted to define comminuted particles having a predetermined size range and such particles are designated by the letter P and supplied in the form of a slurry through an enclosed conduit or line 21, which may be suitably heated, to a cooker 22. The particles are delivered to the cooker with a minimum amount of ambient air and such particles are moved through the cooker at a rate which is sufficient to free the fats from the solid constituents thereby such particles are contained in the cooker for a residence time generally of the order of one hour. The cooker 22 provides optimum heating of the particles due to the provision of fixed internal heating surfaces having a compartively large total area and the provision of unique dualpurpose stirring and cleaning means for the cooker which will be described in detail subsequently.

The cooked particles, designated by the letters CP, are passed over a hooded shaker screen 23 to separate the solids from the free grease and the solids will fall from one end of the screen 23 into a screw conveyor 24 which conveys the solids to a screw press 25 which presses the cooked material to remove any grease remaining therein. The solids from the press are in the form of a meal or pressed cake which is cooled and either stored or further processed, as desired. The vapors from the cooker 22 are processed through a primary condenser 26 causing condensation of water from such vapors and the non-condensed vapors are conveyed to a secondary of barometric condenser 27 for further processing. Cooling water for the condensers is provided from a cooling tower 30 and a more detailed description of the operation of condensers 26 and 27 will be presented subsequently.

INTRODUCING THE ANIMAL PRODUCTS Animal products of the character mentioned above are delivered to a storage hopper 31, see FIGS. 1 and 2, and fed by an auger feed 32 onto a belt conveyer 33. If desired, the animal products may also be introduced as illustrated in FIG. 2 directly from an unloading dock 34 through a suitable chute or conveyor indicated schematically by the arrow 35 ,onto the conveyor 33. The animal products are transferred onto a horizontally arranged conveyor 35 which carries such products past a special metal detector 36 which detects the presence of both magnetic and nonmagnetic metal in such products and in the event metal is detected the detector 36 energizes an ejecting device 37 which serves to deflect the metal-containing animal product off of the conveyor 35 and into an assoicated receptacle or chute (not shown) for removal of the metal and reintroduction of such product onto the conveyor 35 for reinspection by the detector 36.

The animal products are discharged from the end of the conveyor 35, as shown at 40, into a hog 41 of conventional construction which communicates such products within a size range which is capable of being processed in the cooker 22. The particles fall by gravity from the hog 41 ito a surge tank 42 arranged therebeneath, and the surge tank 42 has a restricted area discharge conduit 43 defining its outlet.

DELIVERING THE ANIMAL PRODUCTS TO THE COOKER FREE OF AIR The apparatus and method 20 includes means for delivering comminuted animal products to the cooker 22 with a minimum amount of ambient air. In particular, such means comprises a pump which in this example is a shredding pump 44 installed in the outlet of conduit 43 and a cooperating feed pump 45 connected in the upstream end portion of the enclosed conduit 21 to the cooker 22. The feed pump 45 has an inlet 46 connected in flow communication with a conduit 47 which is connected to the discharge end 50 of the shredding pump 44. During normal operation, the shredding pump 44 is operated so that it delivers a larger amount of comminuted material from the surge tank 42 than the feed pump 45 can convey through enclosed line 21 to the cooker 22 thereby building a substantial pressure in the line 47. A recirculating or by-pass conduit 51 is connected in the line 47 and recirculates the greater amount of comminuted particles away from the inlet of the feed pump 45 into the surge tank 42.

Thus, it is seen that the material from the hog 41 and the material recirculated through conduit 51 maintain a constant head or level or particles at the inlet of the shredding pump thereby substantially excluding ambient air. Further, with the shredding pump 44 delivering communited particles in the form of a slurry to the inlet of the feed pump 45 in a greater quantity than the feed pump delivers through enclosed conduit 21 to the cooker, the pump 45 is kept from introducing air into the enclosed conduit 21 and hence into the cooker 22 whereby the cooker may be operated with greater efficiency under all operating conditions.

The cooker 22 is of unique construction and will be described in detail subsequently; however, the operation of the apparatus and method 20 is such that the cooked products or particles CP exit the cooker 22 through a conduit 52 and are delivered onto a hooded shaker screen 23 whereupon the solids fall by gravity from the end of such screen and are picked up by a screw conveyor 24 and delivered to a screw press 25. These solids are pressed in press 25 in a manner known in the art to define substantially dry meat meal cake and liquid grease and in this example only one press 25 is provided for this purpose as shown in the schemtic of FIG. 1; however, it is to be understood that a plurality of two or more cooperating presses may be provided to receive material from conveyor 24 and as shown by dotted lines in FIG. 2 wherein another press 25A has been added.

The meal cake or meal from press 25 is conveyed by a screw conveyor 53 to a meal cooler 54. Ambient air is provided for cooling the meal in the meal cooler and such air is drawn through a conduit 55; and, the heated air from the meal cooler 54 is drawn through a conduit 56 to a hot well 57 of conventional construction and such air exits the hot well 57 through a conduit 60 to a gas fired odor burner 61 where undesirable odor carrying minute particles are burned and odor-free air ejected through a conduit 62 to atmosphere. The cooled meal is conveyed from the meal cooler 54 by means of a suitable lift or screw conveyor 63 to a pressed meal storage tank 64 and such meal may be further processed or gravity fed from tank 64 through a valve mechanism 65 into a conveying vehicle such as a truck 66.

The grease which falls through the screen 23 by gravity is collected in a surge tank above which the screen is mounted and such grease is pumped from the surge tank 70 through a line 71 using pump 72 into what is often referred to as a clarifier or centrifuge 73. The clarified grease or fat from the centrifuge 73 is conveyed by gravity through a conduit 74 to an intermediate grease storage tank 79. The grease or fat may be pumped from tank 79 to the final storage tank 75, or returned to the surge tank 42 as will be described in more detail subsequently.

The solids from the centrifuge 73 are discharged therefrom and fall by gravity into the screw conveyor 24 which conveys such solids to the screw press 25. The liquid grease from the screw press 25 is conveyed through a line 76 to a collecting tank 77 and is pumped by a pump 78 through a conduit 80 to the forward end of the shaker screen 23 for final recovery of such grease by processing through the grease surge tank 70 and centrifuge 73 as described above.

In some applications of the this invention. it may be desirable to further cook the products exiting the screen 23 and for this purpose a suitable conveying means or conveyor 81 is provided. During normal operation the conveyor 81 conveys to the surge tank 42 any overage of material or products not taken by the screw press 25. In certain instances insufficiently cooked material may also be returned to the surge tank 42 by this route. 1

The fat in intermediate tank 79 may be pumped directly to the final storage tank 75 and for this purpose a pump 85 is provided and connected to one leg of a suitable tee connector 86 which is mounted in flow communication with the bottom of tank 79. The discharge of pump 85 communicates with a conduit 87 which discharges into the tank 75.

It may also be desirable to more precisely control the consistency of the slurry of animal products introduced into the cooker 22. For this purpose fat or grease from the intermediate tank 79 may be pumped back to the surge tank 42 using a pump 88 connected to the opposite leg of the tee connector 86 and the pump 88 connected to a conduit 89 which discharges into the tank 42. The use of controlled amounts of grease or fat in the system reduces the viscosity of the material being cooked in the cooker 22 and improves heat transfer.

The shredding pump 44 is driven by an electric motor which is provided with an electrical control device which includes an ammeter having high and low electric current flow set points. If the bone concentration or viscosity of material pumped by pump 44 gets to high, a high current flow is provided and the high set point actuates pump 88 causing fat to be pumped into the surge tank 42 whereby the load on the pump 44 is decreased until the current flow is below the low set point which turns off pump 88.

PROCESSING VAPORS FROM THE COOKER Vapor-like products from the cooker 22 are introduced into an entrainment separator 90, see FIG. 1, through conduits 91 and such separator separates the solids and foam from the vapors whereby the solids and foam are returned through a line 92 to the cooker and the vapors are conveyed from the separator 90 through a line 93 to the primary condenser 26 which is of a conventional shell and tube type. The water in the vapors introduced into the condenser 26 is condensed and flows through a conduit 106 to the hot well 57. Cooling water is provided through a conduit 104 from the cooling tower 30 and through the tubes of condenser 26 and such cooling water is returned to tow'er 30 through a conduit 94. Make-up water will be required for the cooling tower and such make-up is suitably provided as needed.

The non-condensed and non-condensible vapors or gases are collected in the top of the shell of condenser 27 and are conveyed through a line 95 to the secondary condenser 27 which is commonly referred to as a barometric condenser. The condenser 27 has a conventional steam ejector 96 mounted thereon which has a tailpipe or conduit 97 connected to the hot well 57 and steam for the ejector 96 is provided from a steam boiler 100 through a main conduit 101 and branch conduit 102, and connected to the inlet of such steam ejector.

To assure optimum operating efficiency, the primary condenser 26, secondary condenser 27, and screw press 25 are supplied with comparatively cool water from the cooling tower through the use of a pressure pump 103 and a plurality of suitably interconnected water conditions each of which is given the same reference numeral 104, for simplicity and easy reference thereto. As previously mentioned, the cooling water from condenser 26 is returned to tower 30 through conduit 94; and, the cooling water from press 25 is returned to tower 30 through a conduit 105. However, the cooling water from condenser 27 is conveyed to hot well 57 by a conduit 107.

The vapors from the hooded shaker screen 23 are conveyed by at least one conduit 1 10 to a manifold-like collection conduit 111. Similarly, the vapors from the screw press 25 are also conveyed to collection conduit 11 through at least one line 112. Depending upon the moisture content of these vapors, such vapors may be conveyed to barometric condenser 27 or to steam jet 96 for discharge into hot well 57. The water removed from the vapors in the hot well is discharged to a sewer through a line 115.

As previously mentioned, the cooker 22 is a steamoperated cooker and steam for the cooking operation is provided from the steam boiler through line 101. The steam consumption will vary depending upon operating conditions, the character of the animal products being rendered; however, it is expected that no more than 845 pounds of 100 psig steam will be required for each 1000 pounds of animal products to be rendered.

THE COOKER Reference is now first made to FIG. 4 of the drawings for an overall illustration of the improved cooker 22 which is employed in the apparatus and method 20. The cooker 22 of this example of the invention is shown and described as being operated under subatmospheric pressure conditions. For certain products, the cooker is preferably operated under a partial vacuum of up to approximately 15 inches of mercury.

Although the cooker of this example will now be described as comprised of a plurality of cooker sections operating at subatmospheric pressure conditions, it is to be understood that the entire cooker may also be operated at atmospheric or above atmospheric pressures. Further, the various sections of the cooker 22 may operate at subatmospheric, atmospheric, or above atmospheric pressure conditions in any desired combination. In each of the above instances it will be described that minor plumbing modifications will be required and such modifications would be acheived in accordance with techniques known in the art.

The cooker 22 is essentially of modular construction and comprises a main cylindrical housing which is designated generally by the reference numeral and such housing is comprised of a plurality of housing sections 121 and 122 which are separated by a central partition-123 to thereby define the cooker 22 into substantially two main sections which may also be referred to as cooker sections 121 and 122. The cooker also has a pair of end assemblies or ends 124 and 125 suitably fixed to opposite ends of the housing 120. End 124 defines the inlet end of cooker 22 and is fixed to the outer portion of section 121 while end 125 defines the outlet end of such cooker and hence is fixed to the outer portion of section 122. The forward or inlet end 124 has an inlet opening 127 suitably connected. to enclosed conduit 21 while the outlet end 125 has an opening 130 for discharging cooked material. Each section 121 and 122 of the cooker 22 is separated into three parts or chambers each of which is designated generally by the same reference numeral 126 and the three chambers 126 are defined by a pair of fixed vertical partitions 131.

A central shaft 132 extends longitudinally through the cooker 22 and is supported for rotation at the opposite ends of such cooker by a pair of bearing asemblies 133 and each bearing assembly is supported by an associated end. The shaft 132 is also supported for rotation at locations between its ends by sleeves which may be in the form of sleeve bearings 134. Each partition 131 preferably has its sleeve 134 defining the central portion thereof and the shaft 132 rotates freely in the sleeves 134.

To assure that flow of material is maintained longitudinally through the cooker the intermediate partitions 131 have opening means therein of predetermined area. In particular, each partition has a radius indicated at 135, see FIG. 8, which is less than the inside radius indicated at 136 of its associated cylindrical housing portion, either 121 or 122, whereby a substantially annular space 137 is provided around each partitions 131 with the space 137 being interrupted only by fastening means in the form of lug-like fasteners 138 and inlet and outlet steam flanges 139. The fasteners 138 and flanges 139 are arranged at angularly spaced locations about the circumference of the partition. Each partition 131 also has an enlarged opening 141 provided therein substantially in its top portion with the cooker arranged horizontally. The opening 141 has a substantially semicircular outline, as viewed from an end thereof, and assures that cooked particles tending to stick together to define a comparatively large mass are easily conveyed across the partition 131 while the annular space 137 allows passage of freed fats or grease as well as small cooked particles of material.

Each partition 131 is preferably defined by a pair of spaced parallel plates 142 and each plate 142 has a central opening therewith which receives the sleeve or bearing 134 and the sleeve 134 is fixed to plates 142, see FIG. 7. Similarly, the circumferential edges of the parallel plates 142 comprising each partition have a member 143 fixed thereto. The cutout 141 in each partition is made by forming a cooperating pair of axially aligned cutouts in plates 142 and the peripheral edge of each plate defining the cutout 141 has a substantially semicircular strip 144 fixed thereto, see FIG. 8. The sleeve 134, member 143, and strip 144 are fixed in a fluid-tight manner to define a chamber 145 within each partition 131. The chamber 145 is particularly adapted to receive steam through an inlet opening 146 extending through a flange 139 and discharge condensate and steam through an outlet opening 147 in a flange 139 arranged substantially diametrically opposite inlet opening 146 in the upper portion of the partition.

The partitions 131 define fixed heating surfaces within the central portion of the cooker while controlling axial flow through the cooker. In addition, the cylindrical housing portions 121 and 122 are steam heated as well as inlet and 124 and intermediate partition 123, as will be described subsequently, whereby precisely practically all surfaces of the cooker 22 are precisely heated to assure efficient cooking. Further, although outlet end is not heated in this example, it will be appreciated that such outlet end could be constructed and steam heated in a similar manner as inlet end 124, if desired.

End 124 of cooker 22 is comprised of a central tubular structural member 148, a peripheral structure 149 and a pair of parallel plates 150 which are suitably fixed in position to housing 120 in a conventional manner to define a substantially annular chamber 151 in the end 124 which is similar to chamber 145, see FIG. 7. Similarly, the central partition 123 is comprised of a pair of spaced parallel plates 152 which are fixed at their inner ends to a ring 153 carreid by a fixed sleeve bearing 154 and at their outer ends to a circumferential ring structure 156. The members 152, 153, and 156 are fixed together in a fluid-tight manner to define a substantially annular chamber for the central partition 123.

The steam chambers 151 and 155 comprising end partitions 124 and central partitions 123 respectively are also supplied with steam for heating purposes, and although these chambers could be supplied from a common manifold, if desired, in this example, they are independently supplied. In particular, chamber 151 is supplied with steam through an inlet opening 160, see FIGS. 1 and 5, which is connected to a conduit 161 which is, in turn, connected to the line or conduit 101 from the steam boiler 100. The steam from chamber 151 is discharged through a steam outlet 162 connected to a conduit 163 which is, in turn, connected to a steam conduit 164 which returns condensate to the boiler 100. Similarly, steam for chamber 155 is supplied from steam conduit 101 through a line 165 operatively connected to an inlet opening 166, see FIGS. 1 and 9. Steam from the chamber 155 is discharged through an outlet opening 167 through a conduit 170 which communicates with the conduit 164 for return to the boiler 100.

The cylindrical housing portions 121 and 122 are also steam heated as mentioned earlier. Each portion 122 and 123 is made of a pair of substantially coaxially arranged cylindrical members 171 and 172, see FIG. 7, which are arranged coaxially about shaft 132 in spaced relation. The members 171 and 172 are suitably fixed in a fluid-tight menner between end assembly 124 and central partition 123 to define a substantially cylindrical or tubular chamber 173 therebetween having a volume defined by the difference between the outside diameter of member 172 and inside diameter of member 171 as indicated at 174 and practically the entire axial length of members 171 and 172. The downstream portion 122 of the cooker 22 is defined by two similar tubular members 171 and 172 which also define a volume or chamber 173 therebetween.

As seen particularly in FIGS. 1, 4, 7, steam to each chamber 173 is supplied through an inlet 175 which is supplied by steam conduit 176 connected to the main steam conduit 101 from the boiler. Condensate from each chamber 173 is discharged through a steam outlet 177 which is, in turn, connected to a conduit 180 connected to the return conduit 164 to the boiler.

The inlet openings 146 to the chambers 145 for partitions 131 are in flow communication with chamber 173, see FIG. 8, and are thus supplied with live steam from an associated chamber 173. Similarly, the steam cate with chamber 173 whereby steam exiting the chambers 145 is conveyed away from the cooker 22 through the outlet steam opening 177.

It was pointed out earlier that the cooker 22 is comprised of a plurality of cooking chambers orcompartments 126 with three compartments being provided in each cooker portion 121 and 122.

Each cooking compartment 126 is defined by a pair of substantially planar parallel heating surfaces enclosed by a cylindrical heating surface regardless of whether the cooking compartment 126 is defined between end 124 and an immediately adjacent partition 131, between a pair of partitions 131, or between a partition 131 and the central partition 123. Accordingly, for simplicity of presentation, each substantially planar surface defining each compartment 126 will be designated by the same reference numeral 182. Likewise, each enclosing cylindrical surface defining the circumferential boundary of each compartment 126 and arranged between a pair of associated parallel surfaces 182 will be given the reference numeral 183 regardless of whether it comprises a part of cooker section 121 or 122.

During the process of cooking comminuted animal products in the cooker 22, there is a tendency for cooked particles to adhere to the inside stationary surfaces of the cooker. The cooker 22 provides optimum cooking of the slurry of comminuted animal products introduced therein through inlet 127 with minimum adhering action because it steam heats, without overheating, not only the entire cylindrical cooking surface of the cooker, defined by the adjacent end-to-end cylindrical surfaces 183 but also the comparatively large area defined by the staionary vertical surfaces 182. Further, because the cooker 22 of this example operates under partial vacuum conditions, cooking may be acheived at lower temperature and the large area of the heating surfaces 182 provides heat where it is needed most, in the central portion of the cooker.

The cooker 22 has unique dual-purpose means 184 which assure that cooked particles will not adhere and- /or accumulate on the heating surfaces 182 and 183. In particular, the cooker 22 has a plurality of assemblies 184 which provide the dual purpose of stirring the products in each compartment and cleaning the heating surfaces thereof. As seen in FIG. 7 the assemblies correspond in number to the number of cooking compartments 126 in the cooker 22. Each assembly 184, see FIGS. 7 and 11, is comprised of two sets 185 of members and each set 185 is comprised of a pair of members 186 fixed together in parallel spaced apart relation. The members of each pair are fixed together and around the shaft 132 through the use of fastening flanges 187 fixed to the members 186 and cooperating bolts 188 and nuts 189. In particular, the flanges have semicylindrical surfaces which engage the shaft 132 and the bolts 188 extend through associated aligned openings in flanges 187 and are held by associated nuts 189. To assure that each pair of members 185 doen not rotate about shaft 132 but with such shaft it is preferably keyed thereto by an associated key 190.

Two seats 185 of member 186 are arranged in parallel spaced relation in each compartment 126 and interconnected by suitable structural members 192 extending between the members 186 to define the dualpurpose assembly 184. Each member 192 may have any suitable cross-sectional configuration and, in this example, each member 192 has an L-shaped configuration. Each member 192 is fixed to an L-shaped fastening bracket 193 as by welding and each bracket is fixed to an associated member 186 by threaded screws 194 extending through threaded openings in the member 186.

Each set has a pair of scraper blades 195 fixed thereto and, in this example, each blade has an I..- shaped cross-sectional configuration. Each blade 195 is fixed between two associated sets 185 by welding a pair of brackets 196 to opposite ends thereof. Each bracket 196 is threadedly fastened to an associated member 186 by threaded screws 197 extending through cooperating threaded openings in such member. Each blade 195 preferably has a sharp edge 200 and as the shaft 132 and hence each set 185 is rotated the edges 200 of blades 195 in each set scrape an associated cylindrical heating surface 183 of its cooking compartment 126.

Each dual-purpose assembly 184 also scrapes and cleans both stationary planar vertical surfaces 182 in its cooking compartment. Each surface 182 is cleaned by a pair of scraper blades 201 comprising each set 185 of members 186, see FIGS. 11 and 13. Each blade 201 has a sharpened edge 202 and is provided on its associated member 186 so that it extends from a point inwardly of the longitudinal axis of cooker 22 to the outer extremity of its member. Thus, as each set 185 is rotated by shaft 132 two cooperating blades 201 clean an associated planar heating surface 182.

Each blade 201 may be defined as an integral part of a member 186. However, it is preferably made as a separate piece and detachably fixed to its member to enable easy sharpening of its edge 202 or replacement of the entire blade without the need to discard an associated member 186.

Thus, it is seen that the scrapers 195 and 201 provide scraping of practically the entire inside or heating surfaces of each cooking compartment 126. Further, because a stirring and scraping assembly 184 is provided in each of the plurality of compartments 126 of cooker 22, practically the entire inside surface of the cooker 22 is continously cleaned during the cooking operation. This assures precision steam cooking of comminuted animal particles with minimum likelihood of scorching and efficient rendering of the animal products as they continuously flow through the cooker.

The shaft 132 through the exemplary cooker 22 is operatively connected to a gear box assembly 203 as indicated at 204 in FIG. 4 and assembly 203 is driven by an electric motor 205. The drive for shaft 132 is thus provided only at one end thereof. However, it will be appreciated that the shaft 132 and hence attached assemblies 134 may by driven in any manner known in the art and shaft 132 may be driven by simultaneously driving both ends thereof in a synchronized manner, if desired.

The flow of comminuted animal products-or materials through the cooker 22 is controlled by suitable opening means or openings in the partitions 123 and 131. The openings in the partitions 131 are in the form of annular openings 137 around the periphery of each partition and enlarged openings 141 of substantially semicircular outline, see FIG. 8, with the openings 137 and 141 having fixed flow areas. However, as shown in FIG. 9, the openings through the central partition 123 are in the form of a plurality of roughly semicircular openings 208 the flow area of which may be precisely controlled using externally controlled material flow control means and in this example such externally controlled flow control means comprises a plurality of motor driven gate assemblies 206 corresponding in number to the number of openings 208. Each assembly may be controlled independently of the other assemblies 206 so that the effective fiow area through its associated opening may be varied as required to assure efficient cooking.

Each assembly 206 comprises a suitably supporting structure 207 suitably fixed to the housing portion 120 of cooker 22 and has a gate 210, also see FIG. 10, which is keyed to a shaft 211 (FIG. 7) rotatably supported by structure 207. The shaft 21 1 has an integral gear 212 provided thereon whereby the gate 210, shaft 21 l, and gear 212 are rotatably supported by the supporting structure 207.

The gate 210 is a disc-like gate of approximately semicircular cross-sectional configuration and has a substantially chordal section removed therefrom. Flow is allowed through each gate assembly 206 or opening 208 by rotating its gate 210 so that its removed chordal section is aligned with such opening. Flow through each gate assembly 206 or opening 208 is stopped simply by positioning its gates 210 so that the solid portion of such gates covers the opening.

The gate 210 is moved in a simple manner by a coopcrating driving gear or worm 213 which rotates shaft 21 1. The gear 213 is fixed to a shaft 214 which is operatively connected to a gear box 215 and shaft 214 is driven by an electric motor 216. The motor 216, gear box 215, shaft 214, and gear 213 also comprise the valve assembly 206.

It is a simple matter to control flow through the cooker 22 simply by controlling flow across the central partition 123 by opening one, two, or all three of the gate assemblies 206. Further, the gate assemblies 206 may be selectively opened to control flow by opening the lowermost gate assembly, the uppermost gate assembly, or the intermediate gate assembly in various combinations.

Each gate assembly 206 is of simple and reliable high-strength construction and the gate 210 associated with each assembly is operated merely by rotating its associated shaft 211. The construction of each gate 210 and its associated supporting structure is such that the gate will cursh particles of bone that may tend to obstruct closing or obstruct operation in any manner.

If desired, flow through the cooker 22 may be further precisely controlled through the use of a valve assembly 206 installed in one or more of the partitions 131 with such assembly operating to selectively control flow through an associated opening 141. In addition, to assure optimum continous flow through cooker 22, pneumatic level controls (not shown) of standard construction and operation are preferably connected to the section 122 in accordance with standard practice. Further, such level controls may include associated means for providing a controlled vacuum in the cooker.

The exemplary cooker 22 is comprised of a plurality of very similar sections 121 and 122 whereby such cooker may be considered of modular construction. The construction and design parameters of such cooker are such that it is a simple matter to increase the capacity of such cooker merely by adding one or more sections which may be similar to the section 121. The cooker sections may be simply added as indicated by dotted lines at 220 in FIG. 2. With the addition of cooker sections, it may be necessary to provide another synchronized drive at the opposite end of an elongated central shaft which may extend through the entire cooker whereby another motor 205 and gear box 203 may be used. However, with the cooker construction of this invention which utilizes fixed cylindrical housings and fixed vertical partitions and end plates, it is entirely feasible to interconnect the future cooker sections in flow communication yet drive a central shaft for the added sections independently.

A modification of the cooker 22 of this invention is shown in FIG. 14 of the drawings and such cooker has a central shaft 132 which is provided as two coaxial lengths or shaft portions 132A and 1328 having their near ends supported by the central partition 123 on associated bearing assemblies 225 and 226 respectively carried by partition 123. The assemblies 225 and 226 are capable of taking both axial and radial thrust loads and hold shaft portions 132A and 1328 in spaced relation. In this example and for clarity, the central portion 123 is shown having an exaggerated axial dimension 227.

The shaft portion 132A is driven by a gear box assembly 203 and motor 205 while the shaft portion 1328 is driven by a gear box assembly 230 and motor 231. The shaft portions 132A and 1328 and hence the components carried thereby are driven at different speeds whereby with this arrangement comminuted particles being cooked at one end of the cooker 22 may be mixed or agitated a particular amount while particles being cooked at the opposite end of the cooker may be mixed or agitated a different amount to provide more precisely controlled cooking depending on the products being cooked.

Another modification of the cooker 22 is illustrated in FIGS. 15 and 16 of the drawings wherein it will be seen that a set of members 186 is provided with a pair of additional blades 233 each detachably fastened to an associated member 186 by threaded screws 234. Each blade 233 extends substantially radially from the portion of its member adjoining shaft 132 outwardly beyond the outer edge of such member as shown at 233. Each blade 233 has an easily sharpened edge 236 and the blades 233 and 201 of each set cooperate to assure that their associated planar heating surface 182 is kept clean.

In this disclosure the openings 141 are shown in the top of each vertical partition 131. However, it will be appreciated each opening 141 may be provided in its partition 131 at any desired peripheral position.

GENERAL OPERATION AND CERTAIN EXEMPLARY MODIFICATIONS OF THE OVERALL APPARATUS Having presented a detailed description of the component parts of the apparatus and method of this invention with its unique cooker, it will now be readily apparent that comminuted animal products may be processed through the apparatus and method 20 with optimum efficiency and with minimum use of electrical power, steam and water.

The animal products are introduced from a storage hopper 31 onto a conveyor 33, see FIG. 1, and animal products containing metal are automatically removed and the remaining animal products are introduced into a hog 41 and comminuted into small particles which drop into a storage tank 42. The comminuted animal products are then delivered by shredding pump 44 mounted at the bottom of tank 42 to a feed pump 45 in a volume greater than the output of the feed pump 45 which feeds comminuted particles in slurry form through an enclosed cnduit 21 to the cooker 22. With this overfeeding of pump 45, it is necessary to bypass some of the comminuted particles through a recirculating conduit 51 to the top of the surge tank 42. With this technique of overfeeding pump 45 which in turn is operating continuously to feed enclosed conduit 21, the comminuted particles are introduced into the inlet 127 of the cooker 22 with minimum air.

The exemplary cooker 22 may be operated under a partial vacuum of approximately 13 inches of mercury whereby the comminuted particles are cooked and the fats freed from the solid particles substantially with minimum scorching. The comminuted animal products are cooked in the cooker 22 and are constantly agitated while consistantly scraping practically all of the inside heating surfaces of the cooker.

Vapors from the cooker pass through conduits 91 to an entrainment separaor 90 which separates the vapors .from the solids. The solids are returned to the cooker 21 through a line 92 and the vapors are suitably processed using a system which employs a primary condenser 26, a secondary barometric condenser 27, and a cooling tower 30 to minimize use of cooling water. The non-condensing vapors are introduced into a hot well 57 and conveyed from the hot well to a gas-fired odor furnace 61 and burned whereby odor-free vapors are conveyed to atmosphere through a line 62.

The cooked products from the cooker 22 are passed over a hooded shaker screen 23 to separate the solids from the free grease and the free grease is collected in a surge tank 70. The grease in the surge tank 70 is pumped to a centrifuge 73 and clarified and then conveyed first to an intermediate grease storage tank 79 and finally to a final grease storage tank 75. Solids from the centrifuge 73 are combined with the solids discharging the screen 23 to the inlet of a screw conveyor 24 which conveys the solids to a screw press 25 which removes any remaining grease and the pressed solids in the form of meal or cake are conveyed by a screw conveyor 53 to a meal cooler 54. Vapors from the meal cooler are passed through the hot well 57 and the cooled meal is conveyed by a screw conveyor 63 to a meal storage tank 64. Vapors from the screen 23 and press 25 may be conveyed to the barometric condenser 27 or to steam jet 96 for discharge into hot well 57. In addition, the liquid grease from the press 25 is introduced at the inlet of screen 23.

To assure maximum operating efficiency for the overall apparatus it may be desirable to provide a heat exchanger 240 in the conduit 21 to preheat the comminuted particles before they enter the cooker 22, see FIG. 1. A heated fluid for the heat exchanger 240 may be provided thereto through a conduit 241 and the fluid may be conveyed therefrom through a conduit 242. Heated fluid may be provided from any suitable source and hot vapors from the barometric condenser 27 may be used for this purpose if desired. Alternatively it may be desirable to provide a heated jacket over either a portion of the entire length of conduit 21 to provide the desired heating and the energy for heating the jacket may be from any suitable source including from the barometric condenser 27.

In this disclosure of the invention vapors from the condenser 26 are converted to the secondary or barometric condenser 27; however, it will be appreciated that instead of using the barometric condenser, the vapor system may be suitably modified to employ a positive displacement air pump for processing these vapors and such pump would be installed in the apparatus 20 in accordance with conventional practice.

In some applications of this invention it may be desirable to provide an electrically powered indicator 244 in the event the level of material in the surge tank 42 approaches a minimum level, see FIG. 1. The indicator 244 may be operatively connected by an electrical line 245 to a warning device 246 which may be in the form of a visual alarm such as a light or an audible alarm such as a bell. The indicator 244 may also be provided as part of an automatic control system for pump 45 with such control system being capable of either reducing the speed of pump 45 or stopping such pump to thereby assure a minimum of air is pumped into the cooker 22.

The operation of the apparatus 20 may be improved upon initial starting thereof by heating material which has passed through the shredding pump 44 and recirculating the heated material through by-pass conduit 51 into the surge tank 42. For this purpose a heat exchanger 250 may be installed in the conduit 51, and such heat exchanger may be provided with a suitable hot fluid for heating purposes from any suitable source or such heat exchanger may be heated using any suitable technique known in the art. By using the heat exchanger 250 it is possible to recirculate ground material continously heating it while the tank 42 is being filled whereby starting of the cooker 22 could be delayed until a full load is available in the tank 42. This technique will further decrease operating costs.

As previously mentioned, the cooker 22 may operate in any desired combination of subatmospheric, atmo spheric, or above atmospheric pressure conditions in one or more of its cooker sections. This could be especially effective in poultry operations wherein one or more of the upstream cooker sections would operate at above atmospheric pressure to hydrolyze feathers or break down green bone particles while a downstream section could operate under atmospheric pressure or subatmospheric pressure. The net effect would be to shorten the actual cooking time required.

While the form of apparatus and method herein described constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise form of apparatus and method, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. A cooker for a continous rendering system comprising,

a housing having a cylindrical heating surface extending along substantially its full length and having a pair of opposed ends,

an inlet through one of said ends of receiving comminuted animal products,

an outlet through the other of said ends for discharging said products after cooking thereof,

at least one partition arranged between said ends and in fixed relationship to said housing,

said partition having a pair of opposed planar heating surfaces,

and dual-purpose means rotated within said housing for stirring comminuted particles during cooking thereof and simultaneously scraping both said cylindrical and said planar heating surfaces to prevent sticking and accumulation of products against said cylindrical and said planar surfaces to thereby cause efficient cooking, said dual-purpose means including separate means for scraping said cylindri cal heating surface and separate means for scraping said planar heating surface.

2. A cooker as set forth in claim 1 and further comprising,

a shaft extending axially through said cooker,

means detachably fastening said dual-purpose means to said shaft for rotation therewith,

and drive means for rotating said shaft.

3. A cooker as set forth in claim 1 and further comprising,

opening means in said partition,

and valve means for changing the flow area of said opening means to control flow therethrough and thereby control flow of cooked animal products through said cooker.

4. A cooker as set forth in claim 3 in which said valve means comprises,

a shaft rotatably supported by said housing,

a plate fixed to said housing for rotation therewith,

said plate being adapted to be rotated into and out of position to change said flow area,

and drive means for incrementally rotating said shaft and plate.

5. A cooker as set forth in claim 1 and further comprising,

a first shaft portion extending axially through one end portion of said cooker and being rotatably supported by one of said ends and said partition,

a second shaft portion extending through the other end portion of said cooker and being rotatably supported coaxially with said first shaft portion by the other of said ends and said partition,

means detachably fastening said dual-purpose means to each of said shaft portions,

and drive means for rotating said first and second shaft portions.

6. A cooker as set forth in claim 5 in which said drive means comprises,

a first and second drive operatively connected to said first and second shaft portions respectively,

said drive means being adapted to operate their associated shaft portions at the same rotational speed and at different speeds.

7. A cooker for a continuous rendering system comprising,

a housing having a cylindrical heating surface extending along substantially its full length and having a pair of opposed ends,

at least one of said ends having a fixed inside planar heating surface,

an inlet through one of said ends for receiving comminuted animal products,

an outlet through the other of said ends for discharging said products after cooking thereof,

a plurality of partitions arrranged between said ends, and in fixed relationship to said housing, with each of said partitions having a pair of opposed planar heating surfaces, 7 said partitions separating said housing into a plurality of cooking compartments with each of said 5 compartments being defined by a portion of said cylindricalheating surface and a spaced pair of planar surfaces wherein at least one of said pair of planar surfaces is a heating surface, and dualpurpse means rotated within said housing for stirring comminuted particles during cooking thereof and simultaneously scraping substantially the total area of both said cylindrical heating surface and planar heating surfaces to prevent sticking and accumulation of products thereagainst to thereby assure efficient cooking, said dual-purpose means including first scraping elements for scraping said cylindrical heating surface and second scraping elements for scraping said planar heating surface.

8. A cooker as set forth in claim 7 in which said partitions comprise,

a central partition,

and at least one intermediate partition arranged betwen said central partition and each of said ends, each of said partitions having opening means therein allowing cooked animal products to flow through said cooker.

9. A cooker as set forth in claim 8 and further comprising,

valve means operatively associating with the opening means in said central partition for changing the flow area of its opening means to control flow of said cooked animal products therethrough and hence through said cooker.

10. A cooker as set forth in claim '7 wherein said housing comprises a substantially horizontally arranged cylindrical housing and said planar surfaces are vertically arranged surfaces and further comprising,

a central shaft extending horizontally through said cooker,

a drive means for rotating said shaft,

and means for detachably fixing said dual-purpose means to said shaft for rotation therewith.

l 1. A cooker as set forth in claim 10 in which said dual-purpose means comprises,

a pair of blades in each compartment for scraping the associated portion of said cylindrical heating surface, and a pair of scraper blades for scraping each planar heating surface of each compartment.

12. A cooker as set forth in claim 11 wherein said pair of blades for scraping each planar heating surface are arranged in substantially parallel relation and said pair of scraping blades for scraping said cylindrical heating surface are transverse of and connected to said pair of parallel scraping blades.

13. A cooker as set forth in claim 10 and further comprising,

opening means in each of said partitions,

and valve means for changing the flow area of said opening means in one of said partitions to control flow therethrough and thereby control flow of cooked animal products through said cooker.

14. A cooker as set forth in claim 10 wherein said dual-purpos'e means comprises,

a plurality of assemblies corresponding in number to the number of cooking compartments, each of said assemblies being defined by scraping blades for scraping the cylindrical surface portion and the planar surface of each compartment and associated structural members,

and said scraping blades and structural members cooperating to provide a stirring action.

15. An apparatus for continously rendering animal products comprising,

means for comminuting said products to define particles having a predetermined size range,

cooker for cooking said particles under controlled conditions while continuously moving said particles therethrough at a rate which is sufficient to free the fats from the solid constituents wherein said cooker comprises,

a housing having a cylindrical heating surface extending along substantially its full length and having a pair of opposed ends,

each of said ends having a fixed inside planar surface with the inside surface of at least one end being a heating surface,

at least one partition arranged between said ends and in fixed relationship to said housing,

said partition having a pair of opposed planar heat-i ing surfaces, an inlet through one of said ends for receiving comminuted animal products, an outlet through the other of said ends for discharging said products after cooking thereof, and dual-purpose means rotated within said housing for stirring comminuted particles during cooking thereof and simultaneously scraping substantially the total area of both said cylindrical heating surface and said planar heating surfaces to prevent sticking and accumulation of products thereagainst to thereby assure efficient cooking said dual-purpose means including separate means for scraping said cylindrical heating surface and separate means for scraping said planar heating surface, means for delivering said particles to said cooker with a minimum amount of ambient air, means removing the cooked particles from said cooker, and means separating the free liquid fats from the solid constituents, said delivering means assuring said cooker operates with optimum efficiency due to said minimum amount of ambient air.

16. An apparatus as set forth in claim 15 in which said separating means comprises,

a shaker screen for separating the solid constituents from the free liquid fats, and press means for pressing the solid constituents to remove liquid fats held therein. 17. An apparatus as set forth in claim 15 and further 18 comprising,

a conveyor for conveying pressed meal produced in the screw press by its pressing action to a meal cooler, and means conveying cooled meal to a storage bin. 18. An apparatus as set forth in claim 15 and further comprising,

an entrainment separator operatively connected to said cooker and receiving hot vapors therefrom, said separator separating and returning solids contained in said hot vapors to said cooker and passing vapors therethrough, condenser means operatively connected to receive said vapors from said entrainment separator,

said condenser means separating said vapors into water and non-condensible vapors,

and a cooling tower operatively connected to said condenser means for cooling the condensed water to substantially ambient temperture.

19. An apparatus as set forth in claim 18 in which said condenser means comprises a sheet and tube primary condenser and a cooperating secondary condenser employing a steam ejector.

20. An apparatus as set forth in claim 15 in which said delivering means comprises,

an enclosed conduit connected to the inlet of said cooker,

a feed pump feeding said conduit,

means supplying comminuted particles to the inlet of said feed pump at a substantial pressure and in a quantity greater than the requirements of said cooker,

and means circulating said greater quantity away from said feed pump.

21. An apparatus as set forth in claim 20 in which said supplying means comprises a tank containing comminuted particles,

and said circulating means comprises a recirculating conduit connected upstream of said feed pump and recirculating said greater quantity into said tank.

22. An apparatus as set forth in claim 21 and further comprising,

means heating said greater quantity of particles during flow thereof through said recirculating conduit.

23. An apparatus as set forth in claim 20 in which said supplying means comprises,

a pressure group,

and means introducing comminuted particles into said pressure pump at a substantial head.

24. An apparatus as set forth in claim 15 and further comprising, i

a heat exchanger in said delivering means for heating said particles during flow thereof to said cooker.

UNITED STATES PATENT OFFICE CERTIFICATE .OF CORRECTION PATENT NO. 1 3,899,301

DATED August 12, 1975 INVENTOR(S) Dean K. Bredeson, John R.- Harrison,

Earl A. N. Johnson I It 15 certlfled that error appears In the above-Identified patent and that sald Letters Patent- O are hereby corrected as shown below:

Column 1, line 27 "or" should be of-.

Column 2, line 66 "thereby" should be whereby-.

. Column 3 line 14, "The vapors" should start a new paragraph;

Column 3, line 18, "of" should be -or.

Column 3, line 46, "communicates" should be comminutes.

. Column 3, line 48, "ito" should be --into--.

Column 4, line 8, "or" should be .-of.

Column 5, line 4, omit "the".

Column 5, line 4, the period after "invention" should be a Column 5, line 34, "to" should be too-.

Column 6, line 6, "conditions" should be conduits-.

' Column 6, line 18, "11" should be --111--.

Column 6, line 51, "described" should be appreciated-.

Column 6, line 63, insert 22 after "cooker".

Column 7, line 44, "therewith" should be therein.

Column 7, line 65, "and" should be -end-.

CORRECTIONS CONTINUED ON NEXT PAGE a UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENTNO.: 3,899,301

DATED I August 12, 1975 lN\/ ENTOR(S) I Dean K. Bredeson, John R. Harrison E rl A. N. ,Joh s n It IS certlfled tfi at error appears m the boee-ldenhfled patent and that send Letters Patent are hereby corrected as shown below:

Page 2 Column 7, line 67, delete "precisely".

Column 9, line 59, "pair" should be set-.

. Column 9, line 59, "doen" should be does-.

Column 9, line 61, "seats" should be -sets.

Column 11, line 9, "suitably" should be suitable.

. Column 11, line 47, "cursh" should be crush-.

Column 12, line 4 insert -assemblyafter "box".

Column 12, line 20, "portion" should be --partition-.

Column 13, line 23, "separaor" should be separator-.

Column 13, line 25, "21" should be 22.

Column 13, line 29, "non-condensing" should be non-condensible Column 14, line 2, "converted" should be conveyed.

Column 14, line 63, "of" (second occurrence) should be for.

Column 15, line 9, "cause" should be assure.

Column 15, line 53, "drive means" should be drives-.

Column 16, line 40, delete "means".

CONTINUED ON NEXT PAGE UNI'II'II) S'IA'IES PA'IIfINT OFFICE CERTIFICATE F CORRECTION PATEM Nt). 13,899,301 Page 5 I U t August 12, 1975 I rnvmlok sr Dean K. Bredeson, John R. Harrison, Earl A. N. Johnson i It rs nertrtred that error appears tn the above-rdenhtred patent and that sarrt Letters Patent 0 i are hereby mrrected as shown hetow' IColumn 17, line 38, delete "for' i v IColumn 18, line 48, "group" should be -pump.

Signed and Scaled (I115 twenty-fifth Day of November 1975 suu Arrest:

RUTH C. MASON C. MARSHALL DANN 4119511718 11 (ummissiuucr nflurenls aml Trademarks 

1. A COOKER FOR A CONTINOUS RENDERING SYSTEM COMPRISING, A HOUSING HAVING A CYLINDRICAL HEATING SURFACE EXTENDING ALONG SUBSTANTIALLY ITS FULL LENGTH AND HAVING A PAIR OF OPPOSED ENDS, AN INLET THROUGH ONE OF SAID ENDS OF RECEIVING COMMINUTED ANIMAL PRODUCTS, AN OUTLET THROUGH THE OTHER OF SAID ENDS FOR IS CHARGING SAD PRODUCTS AFTER COOKING THEREOF, AT LEAST ONE PARTITION ARRANGED BETWEEN SAID ENDS AND IN FIXED RELATIONSHIP TO SAID HOUSING, SAID PARTITION HAVING APAIR OF OPPOSED PLANAR HEATIN SURFACES, AND DUAL-PURPOSE MEANS ROTATED WITHIN SAID HOUSING FOR STIRRING COMMINUTED PARTICLES DURING COOKING THEREOF SAID SIMULTANEOUSLY SCRAPING BOTH SAID CYLINDRICAL AND SAID PLANAR HEATING SURFACES TO PREVENT STICKING AND ACCUMULATION OF PRODUCTS AGAINST SAID CYLINDRICAL AND SAID PLANAR SURFACES TO THEREBY CAUSE EFFICIENT COOKING, SAID DUAL-PURPOSE MEANS INCLUDING SEPARATE MEANS FOR SCRAPING SAID CYLINDRICAL HEATING SURFACE AND SEPARATE MEANS FOR SCRAPING SAID PLANAR HEATING SURFACE.
 2. A cooker as set forth in claim 1 and further comprising, a shaft extending axially through said cooker, means detachably fastening said dual-purpose means to said shaft for rotation therewith, and drive means for rotating said shaft.
 3. A cooker as set forth in claim 1 and further comprising, opening means in said partition, and valve means for changing the flow area of said opening means to control flow therethrough and thereby control flow of cooked animal products through said cooker.
 4. A cooker as set forth in claim 3 in which said valve means comprises, a shaft rotatably supported by said housing, a plate fixed to said housing for rotation therewith, said plate being adapted to be rotated into and out of position to change said flow area, and drive means for incrementally rotating said shaft and plate.
 5. A cooker as set forth in claim 1 and further comprising, a first shaft portion extending axially through one end portion of said cooker and being rotatably supported by one of said ends and said partition, a second shaft portion extending through the other end portion of said cooker and being rotatably supported coaxially with said first shaft portion by the other of said ends and said partition, means detachably fastening said dual-purpose means to each of said shaft portions, and drive means for rotating said first and second shaft portions.
 6. A cooker as set forth in claim 5 in which said drive means comprises, a first and second drive operatively connected to said first and second shaft portions respectively, said drive means being adapted to operate their associated shaft portions at the same rotational speed and at different speeds.
 7. A cooker for a continuous rendering system comprising, a housing having a cylindrical heating surface extending along substantially its full length and having a pair of opposed ends, at least one of said ends having a fixed inside planar heating surface, an inlet through one of said ends for receiving comminuted animal products, an outlet through the other of said ends for discharging said products after cooking thereof, a plurality of partitions arrranged between said ends, and in fixed relationship to said housing, with each of said partitions having a pair of opposed planar heating surfaces, said partitions separating said housing into a plurality of cooking compartments with each of said compartments being defined bY a portion of said cylindrical heating surface and a spaced pair of planar surfaces wherein at least one of said pair of planar surfaces is a heating surface, and dual-purpse means rotated within said housing for stirring comminuted particles during cooking thereof and simultaneously scraping substantially the total area of both said cylindrical heating surface and planar heating surfaces to prevent sticking and accumulation of products thereagainst to thereby assure efficient cooking, said dual-purpose means including first scraping elements for scraping said cylindrical heating surface and second scraping elements for scraping said planar heating surface.
 8. A cooker as set forth in claim 7 in which said partitions comprise, a central partition, and at least one intermediate partition arranged betwen said central partition and each of said ends, each of said partitions having opening means therein allowing cooked animal products to flow through said cooker.
 9. A cooker as set forth in claim 8 and further comprising, valve means operatively associating with the opening means in said central partition for changing the flow area of its opening means to control flow of said cooked animal products therethrough and hence through said cooker.
 10. A cooker as set forth in claim 7 wherein said housing comprises a substantially horizontally arranged cylindrical housing and said planar surfaces are vertically arranged surfaces and further comprising, a central shaft extending horizontally through said cooker, a drive means for rotating said shaft, and means for detachably fixing said dual-purpose means to said shaft for rotation therewith.
 11. A cooker as set forth in claim 10 in which said dual-purpose means comprises, a pair of blades in each compartment for scraping the associated portion of said cylindrical heating surface, and a pair of scraper blades for scraping each planar heating surface of each compartment.
 12. A cooker as set forth in claim 11 wherein said pair of blades for scraping each planar heating surface are arranged in substantially parallel relation and said pair of scraping blades for scraping said cylindrical heating surface are transverse of and connected to said pair of parallel scraping blades.
 13. A cooker as set forth in claim 10 and further comprising, opening means in each of said partitions, and valve means for changing the flow area of said opening means in one of said partitions to control flow therethrough and thereby control flow of cooked animal products through said cooker.
 14. A cooker as set forth in claim 10 wherein said dual-purpose means comprises, a plurality of assemblies corresponding in number to the number of cooking compartments, each of said assemblies being defined by scraping blades for scraping the cylindrical surface portion and the planar surface of each compartment and associated structural members, and said scraping blades and structural members cooperating to provide a stirring action.
 15. An apparatus for continously rendering animal products comprising, means for comminuting said products to define particles having a predetermined size range, cooker for cooking said particles under controlled conditions while continously moving said particles therethrough at a rate which is sufficient to free the fats from the solid constituents wherein said cooker comprises, a housing having a cylindrical heating surface extending along substantially its full length and having a pair of opposed ends, each of said ends having a fixed inside planar surface with the inside surface of at least one end being a heating surface, at least one partition arranged between said ends and in fixed relationship to said housing, said partition having a pair of opposed planar heating surfaces, an inlet through one of said ends for receiving comminuted animal products, an outlet through the other of said ends for discharGing said products after cooking thereof, and dual-purpose means rotated within said housing for stirring comminuted particles during cooking thereof and simultaneously scraping substantially the total area of both said cylindrical heating surface and said planar heating surfaces to prevent sticking and accumulation of products theragainst to thereby assure efficient cooking said dual-purpose means including separate means for scraping said cylindrical heating surface and separate means for scraping said planar heating surface, means for delivering said particles to said cooker with a minmum amount of ambient air, means removing the cooked particles from said cooker, and means separating the free liquid fats from the solid constituents, said delivering means assuring said cooker operates with optimum efficiency due to said minimum amount of ambient air.
 16. An apparatus as set forth in claim 15 in which said separating means comprises, a shaker screen for separating the solid constituents from the free liquid fats, and press means for pressing the solid constituents to remove liquid fats held therein.
 17. An apparatus as set forth in claim 15 and further comprising, a conveyor for conveying pressed meal produced in the screw press by its pressing action to a meal cooler, and means conveying cooled meal to a storage bin.
 18. An apparatus as set forth in claim 15 and further comprising, an entrainment separator operatively connected to said cooker and receiving hot vapors therefrom, said separator separating and returning solids contained in said hot vapors to said cooker and passing vapors therethrough, condenser means operatively connected to receive said vapors from said entrainment separator, said condenser means separating said vapors into water and non-condensible vapors, and a cooling tower operatively connected to said condenser means for cooling the condensed water to substantially ambient temperture.
 19. An apparatus as set forth in claim 18 in which said condenser means comprises a sheet and tube primary condenser and a cooperating secondary condenser employing a steam ejector.
 20. An apparatus as set forth in claim 15 in which said delivering means comprises, an enclosed conduit connected to the inlet of said cooker, a feed pump feeding said conduit, means supplying comminuted particles to the inlet of said feed pump at a substantial pressure and in a quantity greater than the requirements of said cooker, and means circulating said greater quantity away from said feed pump.
 21. An apparatus as set forth in claim 20 in which said supplying means comprises a tank containing comminuted particles, and said circulating means comprises a recirculating conduit connected upstream of said feed pump and recirculatng said greater quantity into said tank.
 22. An apparatus as set forth in claim 21 and further comprising, means heating said greater quantity of particles during flow thereof through said recirculating conduit.
 23. An apparatus as set forth in claim 20 in which said supplying means comprises, a pressure group, and means introducing comminuted particles into said pressure pump at a substantial head.
 24. An apparatus as set forth in claim 15 and further comprising, a heat exchanger in said delivering means for heating said particles during flow thereof to said cooker. 